Strategy Discussion Defense Secretary Jim Mattis speaks with Colin S. Gray, director of the Centre for Strategic Studies, during a trip to London, April 1, 2017. DoD photo by Army Sgt. Amber I. Smith SHARE IMAGE: Download Image: Full Size (1.25 MB) Tags: Travels , JIm Mattis, SecDef Photo By: Amber I. Smith VIRIN: 170401-D-SV709-044T.JPG Photo Gallery